The kidney cleansing herbs that Andreas Moritz recommends in his liver/gallbladder flush book saved my life recently in terms of lower back pain caused by kidney stones! I highly recommend them, they seemed to start working almost immediately upon drinking them.
Moritz believed we get kidney stones by having a backed up liver/galbladder which is very common in our over acidic bodies. People of all diets (meat and vegetarian eaters) can get gallstones.